i6 



SCIENCE-GOSSIP. 



tude, g''j inch [= 4 millimetres]; length of hori- 

 zontal fold at aperture, ^j. inch [= 5 millimetres]. 

 Basal denticle [i.e. vertical parietal plate] cup- 

 shaped." 



From figs. 75^ and e, which have been copied 

 from Dr. Bagg's sketches, it appears that the 

 parietal armature consists of a strong vertical 

 plate which is concave posteriorly ; on the 

 posterior side there are three short horizontal 

 folds, the upper longest, the median shortest ; a 

 short horizontal fold at the aperture is united to 

 the flexuous ridge (see fig. 751;, which shows the 

 parietal wall) ; while the palatal armature appears to 

 consist of six folds : the first three short and hori- 

 zontal ; the fourth strong, vertical, slightly indented 

 about the middle; the fifth and sixth horizontal and 

 thin (see fig. 75^, which gives the posterior aspect 

 of both armatures). Figs, y^a-c are reproduced 

 from the photographs of the type specimens, en- 

 larged two diameters. Mr. W. T. Blanford has 

 recorded the following additional habitats for this 

 species: Pegu and Tenasserim (in "British Burma 

 Gazetteer" (1879), i. p. 709). 



Plectopylis leiophis (figs, jba-c) from Thayet Myo, 

 Pegu, was described by Mr. Benson in the 



^^^fe 



b c 



Fifi. yd.— PUctupylii leiophis. 



"Annals and Magazine of Natural History" (3), 

 v. (iSGo), p. 246, and illustrated by Lieut. -Colonel 

 Godwin-Austen in the " Proceedings of the 

 Zoological Society," 1874, t. 74, fig. 2, who 

 subsequently {ibid. 1875, p. 44) stated that this 

 shell was identical with Dr. Gould's P. refiiga, 

 basing this identification on the specimens in the 

 British Museum, so labelled by Mr. Cuming. 

 Upon comparing these latter with Mr. Benson's 

 type specimens, obligingly lent to me by Mr. 

 Harmer, of the University Museum of Zoology, 

 Cambridge, I found they were certainly identicnl, 

 but as already stated, the specimens in the 

 British Museum were wrongly identified. They 

 formed the subject of the illustrations purporting 

 to represent P. refiiga in Dr. R. A. Philippi's 

 " Beschreibungen und Abbildungen neuer oder 

 wenig gekannter Conchylien," iii. Helix, t. 10, f. 4; 

 in Reeve's " Conchologia Iconica," t. 82, f. 436, 

 and in " Martini und Chemnitz, -Conchylien 

 Cabinet " (2), i. t. 66, ff. 21-23. All these figures. 



therefore, must be referred to P. leiophis. This 

 species was also figured in Hanley and Theobald's 

 " Conchologia Indica," t. 13, f. 8. In addition to 

 the original habitat, the species has been found at 

 Kivadouk, and Akoutoung on the Irawady, below 

 Prome (W. T. Blanford, Journ. As. Soc, Bengal, 

 xxxiv. (1865), p. 75). I very mucli doubt that 

 Mr. Benson was acquainted with Plectopylis refiiga, 

 although Mr. Blanford believes he knew the 

 species. Mr. Benson, in discussing P. leiophis (Ann. 

 Mag. Nat. Hist. (3), v. (i860), p. 246), mentions, it is 

 true, P. refuga var dextrorsa, but this form, as has 

 already been shown, is allied to P. brachydisais 

 (c.f. Science-Gossip, iii. p. 154) and is quite distinct 

 from P. rejtiga and P. leiophis. A specimen in the 

 McAndrew Collection, in the University Museum 

 of Zoology at Cambridge, which contains Mr. 

 Benson's types, is labelled P. refuga, but I refer 

 this without hesitation to a form of P. achatina. 

 P. leiophis is sinistral, discoid, pale rufous-corneous, 

 finely and regularly striated, decussated by micro- 

 scopic spiral lines on the upper surface, spirally 

 wrinkled at the side and below. The spire is 

 depressed, the apex raised a little above the plane 

 of the other whorls, and the suture impressed. 

 There are six and a-half narrow rounded whorls, 

 which increase very slowly and regularly ; the last 

 being angulated above the periphery, shortly and 

 abruptly descending in front, widening a little 

 towards the aperture, and slightly constricted 

 behind the peristome. The aperture is roundly 

 cordate, oblique ; the peristome white, thickened 

 and reflected ; the margins converging and united 

 by a raised curved ridge on the parietal callus, 

 slightly notched at the lower junction. The um- 

 bilicus is wide and moderately deep. The parietal 

 armature consists of a strong vertical plate, 

 angular above, where it gives off posteriorly an 

 abruptly descending short ridge, while below it 

 deflects obliquely, and on the anterior side it 

 gives off a short horizontal fold ; a long free 

 horizontal fold rises close to the vertical plate a 

 little below its upper extremity, revolving parallel 

 with the whorl as far as the aperture, where it 

 unites with the ridge on the parietal callus ; 

 between this fold and the lower one just referred 

 to, occurs a very short, free, horizontal fold, but this 

 does not appear to be constant, as it is absent in a 

 specimen in Mr. Blanford's collection, while in 

 an immature specimen in my collection, it appears 

 as two small coalesced folds, and in this instance 

 an additional elongated denticle occurs between 

 it and the upper long fold ; in all the other speci- 

 mens examined, however, the parietal armature is 

 identical with that of the type specimen. A very 

 thin, free horizontal fold rises below the vertical 

 plate, running close to the lower suture, and 

 terminating close to the ridge at the aperture. The 

 palatal armatu'-e is composed of six folds, five 



